枚举枚举的Java自定义枚举值 [英] Java custom enum value to enum

问题描述

我有这样的枚举

public enum Sizes {
    Normal(232), Large(455);

    private final int _value;

    Sizes(int value) {
        _value = value;
    }

    public int Value() {
        return _value;
    }
}

现在我可以调用Sizes.Normal.Value（）获取整数值，但是如何将整数值转换为枚举？

Now I can call Sizes.Normal.Value() to get integer value, but how do I convert integer value back to enum?

我现在所做的是：

public Sizes ToSize(int value) {
    for (Sizes size : Sizes.values()) {
        if (size.Value() == value)
            return size;
    }
    return null;
}

但这只是方法吗？这就是Java的工作原理？

But that's only way to do that? That's how Java works?

推荐答案

是的，这是怎么做的，一般通过在枚举中添加静态方法。想想吧你可以在这个枚举上有10个字段。你希望Java设置所有的查找？

Yes that's how it's done, generally by adding a static method to the enum. Think about it; you could have 10 fields on the enum. Do you expect Java to set up lookups for all of them?

这里的意思是Java枚举没有值。他们有身份和秩序，加上你为自己添加的任何东西。这与C＃不同，C＃中的C ++具有任意的整数值。

The point here is that Java enums don't have a 'value'. They have identity and an ordinal, plus whatever you add for yourself. This is just different from C#, which follows C++ in having an arbitrary integer value instead.

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